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Calculation Of Estimated Blood Alcohol Concentration (BAC)

Body Weight: Calculations are for people with a normal body weight for their height, free of drugs or other affecting medication and neither unusually thin nor obese.

Drink Equivalents: 1 drink equals:

1½ oz rum, rye, scotch, brandy, gin, vodka, etc.

1 12-oz. bottle normal-strength beer

3 oz fortified wine

5 oz table wine

Using the Chart: Find the appropriate figure using the proper chart (male or female), body weight, and number of drinks consumed.

Then subtract the time factor (see Time Factor Table Below) from the figure on the chart to obtain the approximate BAC. For example, for a 150-lb. man who has had 4 drinks in two hours, take the figure .116 (from the chart for males) and subtract .030 (from the Time Factor Table) to obtain a BAC of .086%

Time Factor Table

Hours Since
First Drink
Subtract from BAC
1
.015
2
.030
3
.045
4
.060
5
.075
6
.090

MALES

Number
of
Drinks
Ideal Body Weight
(lbs.)
100
125
150
175
200
225
250
1
.043
.034
.029
.025
.022
.019
.017
2
.087
.069
.058
.050
.043
.039
.035
3
.130
.103
.087
.075
.065
.058
.052
4
.174
.139
.116
.100
.087
.078
.070
5
.217
.173
.145
.125
.108
.097
.087
6
.261
.209
.174
.150
.130
.117
.105
7
.304
.242
.203
.175
.152
.136
.122
8
.348
.278
.232
.200
.174
.156
.139
9
.391
.312
.261
.225
.195
.175
.156
10
.435
.346
.290
.250
.217
.195
.173

FEMALES

Number
of
Drinks
Ideal Body Weight
(lbs.)
100
125
150
175
200
225
250
1
.050
.040
.034
.029
.026
.022
.020
2
.101
.080
.068
.058
.050
.045
.041
3
.152
.120
.101
.087
.076
.068
.061
4
.203
.162
.135
.117
.101
.091
.082
5
.253
.202
.169
.146
.126
.113
.101
6
.304
.244
.203
.175
.152
.136
.122
7
.355
.282
.237
.204
.177
.159
.142
8
.406
.324
.271
.233
.203
.182
.162
9
.456
.364
.304
.262
.227
.204
.182
10
.507
.404
.338
.292
.253
.227
.202
 
 
 

Last Updated 1/25/07